A circumpolar current becomes possible

node

The opening of Drake Passage and the deepening of the Tasman gateway removed the last land barriers between the Atlantic, Pacific and Indian oceans at southern high latitudes, allowing an unbroken eastward current around Antarctica. When this happened is genuinely disputed: estimates cluster around the Eocene–Oligocene transition near 34 Ma, around 31 Ma from foraminiferal and neodymium evidence, near 30 Ma from gateway–westerly alignment arguments, and near 24 Ma from flow-speed and water-mass homogeneity records, while a 2023 study argues the modern ACC was not established until the late Miocene. The pack states the disagreement rather than choosing.

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Ocean CurrentsOcean

Evidence · 1

Late Miocene onset of the modern Antarctic Circumpolar Current

Timeline

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Connections · 3

Antarctic Circumpolar Current (ACC)concerns
Drake Passageconcerns
Southern Oceanconcerns

Assembled narrative · 1

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Observed changes · 0

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/atlas?object=EVT_ACC_ONSET